Restoration presents a global challenge in drylands (arid and semiarid ecosystems) where uses can range from exclusive conservation to open-pit mining and restoration practices are constrained by scarce, unpredictable precipitation, and high ambient temperatures. Adding woodchip amendments to soils is a common strategy for mitigating soil degradation as amendments may enhance soil carbon and increase plant cover. We assessed the effect of surface or incorporated woodchip addition and incorporated wood-derived biochar on soil carbon dynamics and microbial activities as well as plant cover in semiarid soils that had been removed and replaced.We found that woodchips at the soil surface increased soil organic carbon (SOC), and both surface and incorporated woodchips increased the dissolved organic carbon (DOC) content. The incorporation of woodchips inhibited plant cover yet increased soil CO2 efflux and dissolved organic matter stoichiometry. Surface woodchips also significantly enhancedmicrobial activities but not plant cover. A significant amount of the soil efflux in response to incorporating woodchips was explained by plant cover and exoenzyme activities, but this was not the case for other amendment treatments. Biochar, thought to be more resistant to decomposition, neither stimulated nor reduced microbial activities or plant cover and did not influence SOC or DOC. Our findings demonstrate that the influence of woodchip amendments on microbial processes and soil carbon dynamics depends on the location of application and that coarse fast-pyrolysis biochar has limited influence on soil processes over a 22-month study in a water-limited ecosystem.

中文翻译：

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木屑和生物炭改良剂对微生物反应的影响不同，但不会提高受干扰的半干旱土壤中的植物恢复

恢复对旱地（干旱和半干旱生态系统）提出了一项全球性挑战，其中的用途范围从专属保护到露天采矿，恢复实践受到稀缺、不可预测的降水和高环境温度的限制。向土壤中添加木片改良剂是缓解土壤退化的常用策略，因为改良剂可以增加土壤碳并增加植物覆盖。我们评估了表层或掺入木片以及掺入木源生物炭对土壤碳动态和微生物活动以及已被移除和替代的半干旱土壤中植物覆盖的影响。我们发现土壤表面的木片增加了土壤有机碳(SOC)，表面和掺入的木片都增加了溶解有机碳 (DOC) 的含量。木片的掺入抑制了植物覆盖，但增加了土壤 CO2 流出和溶解有机物质的化学计量。表面木片也显着增强了微生物活动，但没有增强植物覆盖。植物覆盖和外酶活性解释了大量土壤外排对加入木片的反应，但其他修正处理并非如此。生物炭被认为更耐分解，既不刺激也不减少微生物活动或植物覆盖，也不影响 SOC 或 DOC。我们的研究结果表明，木屑改良剂对微生物过程和土壤碳动态的影响取决于应用的位置，并且在 22 个月的缺水生态系统研究中，粗快热解生物炭对土壤过程的影响有限。